This invention relates generally to plasma cutting torches, and is more specifically directed to an electrode for plasma cutting torches that has a superior service life.
Plasma cutting torches incorporate electrodes which generate a plasma arc which is used for the cutting of metals or other materials. Plasma cutting torches are widely found and used in the prior art. Electrodes currently found in the prior art are characterized by a conductive casing, which is normally copper, which encompasses the electrode insert. This insert is generally concentric with the casing, but of smaller diameter, and is generally made of hafnium, zirconium, or tungsten. This insert is fixed by a friction fit within the casing, and is not designed to be moveable, removeable, or replaceable.
In use, the insert erodes so as to form a crater in the electrode insert. When the crater depth in the electrode reaches approximately 0.050 to 0.060 inches, the performance of the electrode depreciates to a level which makes it unusable. Since, in the prior art, the insert is fixed within the conductive casing, the entire electrode is discarded. Under normal cutting conditions, electrodes must be replaced after two hours of use for hafnium or zirconium inserts when used with air or oxygen as the plasma forming gas. Accordingly, the expense associated with the electrodes found in the prior art is high.